This longitudinal study addresses the relationship between birth weight and early childhood caries (ECC) in a cohort of pre-term very low birth weight (VLBW) and full-term normal birth weight (NBW) infants. VLBW and ECC disproportionately affects poor and minority children costing Medicaid billions of dollars annually for treatment. The improved survival of VLBW children has resulted in greater long-term disabilities and need for health services, thus classifying them as children with special health care needs. The oral health needs of VLBW children have not been adequately studied. VLBW children are known to have a high prevalence of enamel defects in the primary dentition, which in turn can lead to increased susceptibility to ECC. Socio- behavioral factors that can predispose some children to ECC are unknown in VLBW children. Therefore the primary aims of the study are to (1) assess the incidence of ECC in VLBW and NBW infants; (2) assess mediators such as the incidence of developmental enamel defects, S.mutans infection and the extent of oral health behaviors in VLBW and NEW infants; (3) assess the indirect relationship between birth weight and ECC via mediators after controlling for independent moderating variables. A total of 200 VLBW and 200 NBW infants will be followed at 8 and 18-20 months corrected age. The proposed study will collect data on caries (decayed and filled surfaces), mediating biological variables (enamel hypoplasia and opacity, S.mutans levels) and infant oral health behavior (feeding, diet, oral hygiene practices, and dental access), and independent variables (demographics, parent predisposing, enabling, need characteristics, dental behavior, biological and child medical factors). Data analysis for testing aims 1 and 2 includes the generalized estimating equations (GEE) models, and a two-stage structural equations model (SEM) for testing the role of mediators in aim 3. The sample size provide 85 to 99% power to compare the two groups in terms of the three study aims. The results of this study will provide critical data to address the knowledge gaps in taking care of VLBW children. The clinical implications include primary prevention, early diagnosis and treatment to prevent further susceptibility to dental decay. It is also of public health interest since interventions to target knowledge, attitude, beliefs, and oral health practices can be implemented in programs for special needs children, and there by improve both oral and systemic health.